Title: Expression of p53 Protein in oral Squamous Cell Carcinomas and its comparison with a well established Grading system for Histopathological Malignancy
Abstract: Objectives: To evaluate the use of p53 as indicator of tumour prognosis in routine biopsies of oral squamous cell carcinomas and its comparison with a well established grading system for histopathological malignancy.Materials and methods: A total of 20 patients with age ranging from 45-70, diagnosed as clinically malignant and 20 normal controls were selected for the study.One group of sections of the biopsy specimens was stained for routine H & E and the other group was used for immunohistochemical study The technique used in this kit is based on the labeled streptavidin-biotin method.Statistical analysis: All the cases were reviewed and classified according to the modified histological malignancy grading system.The analysis of p53 positive cells was performed using Diracom 3, image processing software.The percentage of positive p53 nuclei was then calculated.The Pearson correlation coefficient test was used to evaluate the relationship between the percentage of tumoral p53 Positive cells and the total score of malignancy and the relationship between the percentages of tumoral p53 positive cells with each of the parameters of the malignancy grading system.Results: All the 20 cases had a clear positive reaction to p53.Nuclear p53 staining was found only in epithelial cells.Positivity of p53 staining shows a correlation with the individual histological grading criteria, related to the tumour cell population (degree of keratinisation, nuclear polymorphism, and number of mitosis.However there was no correlation between the p53 and the individual histological grading criteria expressing tumour host relationship as inflammatory infiltrate and pattern of invasion.Conclusion: Altogether, these data indicated that p53 protein is related to tumour cells, but not involved with either the tumour architecture or the host response.Therefore, a significant association between p53 over expression and high grade of malignancy has been found.